Electric switch and circuit for telephone systems



(No Model.)

J. W. BRENNAN.

ELECTRIC SWITCH AND CIRCUIT ECR TELEPHONE SYSTEMS.

No. 267,059. Patented NCV.'7,1882..

N. PETERSA Pholo-Lilhagmphnr. wwvnglm. D, C.

UNITED STATES PATENT OFFICE,

JAMES 'W. BRENNAN, OF CHICAGO, ILLTNOIS.

ELECTRIC SWITCH AND CIRCUIT FOR TELEPHONE SYSTEMS.

SPECIFlCATIONforming part of Letters Patent No. 267,059, dated November *7, 1882, Application filed April 4, 1382. (No model.)

To all whom it may concern Be it known that I, JAMES W. BRENNAN, a citizen of the United States, residing at Ghieago, county ot' Cook, and State of Illinois, have invented certain new and useful Improvements in Electric Switches and Telephone or Telegraph Systems, of which the following` is a full, clear, and eXact description, reference being had to the accom panying drawings, in which- Figure l shows in plan view my improved electric switch connected up at an intermediate-line station with the other parts or instruments made necessary to the operation of my improved system ot' circuits. Fig.'2 is a moditied form ot' the improved switch, showing the contact-plates arranged in circular form'.

Prior to my invention when two distinct loops or circuits ran into the same station in an electro-telephonie system-as, for example, when the station was included in a line from a central otlice or general exchange and in a private line as well--it'each ofthe loops were connected up with the same set of instruments-that is to say, with a telephonie receiver, transmitter, and audible signal, so that this single set ot' instruments could be used to operate at will in either circuitit followed, from the nature of the switch employed, that when the i'nstrunients were thrown into one loop to receive and transmit messages the other loop would be broken and no signal be given if ett'ort were made to call the station from any point in the broken loop. Thus, for example, if the operator were receiving and transmitting over the main line through the central oiiice, the private-line loop would stand open, so that he would not be apprised ot' any call directed to the station troni over said broken circuit. A neglect lto return the switch to position at'- ter use ot' the telephone-instruments would still further prolong the cut-out, leaving the station practically isolated over the line with its circuit broken, and thus giving rise to much trouble and annoyance.

My invention is designed to maintain both loops of an electro-telephonie system, such as described, in permanently-closed circuit, so that whether the instruments at the station be connected up for use in either loop a call to the station from over the other loop will always be sounded at the station.

'lo this end the invention consists ot" a certain improved shifting switch, as hereinafter described and defined in claims, and in thecombination therewith-ot'two distinct loops or liliecircuits, a single set ot' telephone-instruments and connected signals, and an extra audible signal, so that whenever one circuit is directed through the telephone-instruments the other will pass through the extra audible signal, and thus, with bot-h loops permanently closed, the operator at the station be always apprised of a call coming to it from either circuit. By the substitution of the improved forni of switch and the addition of a simple magneto-signal one set of telephone-instruments may be conveniently used for duty in either one ot' two separate circuits at a material reduction in cost of maintaining the station and with increased etticiency of operation.

As shown in Fig. l, the switch-lever A, consisting of a straight bar of gutta-percha ot like insulating material, is pivotcd at a to a baseboard, and carries on its lower face the contact-pieces b b c c', projecting from said bar on either side, the end contact-pieces, l) b', bcing somewhat longer than the intermediate contact-pieces, c c', whereby they may engage the outer contact-plates, el d and c c', while the inner plates, fj" g g', are borne upon by the contact-pieces 0 c. Each one of the several contact pieces and plates` is carefully insulated from all ot' its `fellows, the platesbeing secured to the same base-board to which the switchlever is pivoted. The telephone-instruments and connected signal are shown at B in a short loop-wire,one end ot' which is in electrical connection with the outer plate c', and the other end with the inner plate g. For simplicity of illustration the local battery, induction-coil, and switch ot' the telephone-instruments are not shown, as their mode ot' connection is well known and forms no part of the presentinvention.

The extra audible signal is shown at C, being in this case an ordinary electro-magnet bell sounder situated in a short wire loop, one end ot' which is connected up with the inner contact-plate g', and the other end with the outer IOC) contact-plate c. 0f the two main-line loops or circuits, the wires it" of one are shown connected up with the inner contact-platef and the outer contact-plate d, respectively, and the wires k k of the other are shown in electrical connection with the inner contact-plate fa-nd with the outer contact-plate d, respectively. 1f, now, the switch-lever is in the position shown in i'ull lines, Fig. l, the course of a current from the main-line wire k, for example, is through theinner contact-platef, short contact-piece c', inner contact-plate g', telephoneloop andinstrument,B,returningthence to outer contact-plate e', contact-piece b, outer plate Land to line-wire it', and so to ground, or tothe next station. At the same time a current over the linc-wiret'would pass by contact-plate f, contact-piece c, contact-plate g, and short loop-wire to the extra bell-sounder 0, returning bythe loop to contact-plate e, contact-piece b, contact-plate d', and line-wire 'i' to ground, or to the next station. Hence it follows that both main-line circuits are permanently closed by the switch ofthe station, and thus it' the operator be receiving or transmitting a message at the telephone-instruments over main line 7c la a call to the station from over the other main line, t t, will be sounded forthwith at the signal U. The operator, being made aware ofthe new summons, can respond thereto as soon as convenient, and by shifting the lever A to the position shown by dotted lines willso far reverse conditions that the current from theloop t"will pass through the telephone-instruments, and that from the loop t It will pass through the extra signal O.A This is accomplished by the changed relation ot' the contact-plates to the contact pieces ot' the switch-lever, and as the other connections remain the same the course ofthe circuits in the new relation of the parts may be readily traced by those familiar with the art without need of further detailed description.

It will be noted that in either position of the switch-lever the signal usual to the set of telephone-instruments and the extra signal (shown at C) will be in separate circuits; and so if the telephone-instruments proper be not in actual use the operator at the station will yet be made aware of a call coming over either circuit.

The switch shown in Fig. 2 does not differ from that heretofore described, except that the eight contact-plates are arranged in circular form instead of in inner and outer sets of four plates each in rectangular method, as shown in Fig. l. In the modified torni there is a pivotcd switch-lever, A, of gutta-percha, or the like, and to this lever are attached the cross contact arms or pieces b b c c', as before. rlhe connections of this form of switch with the line-circuits and with the short loops of the station containing the telephone set and the extra signal respectively do not dift'cr from what were heretofore defined for Fig. l, and

may be readily traced without need oipresentl repetition.

"I have thus far described my invention as applicable to a telephonie system; but it is manifest that in like manneritmay be adapted to a telegraphic system, so that a single relay and sounder may do duty at will in either one of two separate circuits, and this by addition ot' an extra sounder, as hereinbefore set forth.

Vhile the forms of switch as described are particularly applicable to telephone or telegraph stations, they maybe used with equal success wherever it is desired to maintain two electric loops in closed circuit, and to shift the several devices or pieces ot' apparatus at will from one circuit to the other.

Having thus described the invention, what I claim, and desire to secure by Letters Patent, 1s-

l. An electric switch for two distinct loops or circuits, said switch consisting of apivoted lever-arm having a series of contact-pieces secured thereto, in combination with a series ot' contact-plates arranged, substantially as described, to meet said contact-pieces, so that the loops or circuits may be closed in either position of the switch-lever, substantially as set forth.

2. In electric telephone or telegraph systems, the combination, with a single set of receiving and transmitting instruments having the usual audible signal, of an extra audible signal and a shifting switch, substantially as described, by which two distinct loops or sets ot' main-line wires may be maintained in closed electric circuit, the one through the instruments and the other through the extra signal, or reversely, substantially as set forth.

3. In electric telephone or telegraph systems, the combinatioiuwith a single set otl receiving and transmitting instruments having the usual audible signal, ot' an extra audible signal and a shifting switch,whichsaid switch consists of a pivoted lever-arm carrying a series of contact-pieces, and of a series of contact-plates arranged, substantially as set forth, to meet and coact with said contact-pieces, the entire combination being such that two distinct loops or sets of main-line wires may be maintained in closed electric circuit, the one through the instruments and the other through the extra signal, substantially as dcscribed.

JAMES XV. BRENNAN.

Witnesses:

JAMES H. Panton, GEORGE P. Frsunn, Jr.

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